Percutaneous transluminal coronary angioplasty (PTCA) is a therapeutic medical procedure used to increase blood flow through the coronary artery and can often be used as an alternative to coronary by-pass surgery. In this procedure, the angioplasty balloon is inflated within the stenosed vessel in order to disrupt the wall components of the vessel to obtain an enlarged lumen. With respect to arterial stenosed lesions, the relatively incompressible plaque remains unaltered, while the more elastic medial and adventitial layers of the body passageway stretch around the plaque.
Self-expanding stents that are radially and axially flexible have been developed that are composed of a plurality of flexible elements that form a self-expanding helix. These stents are implanted to open or dilate tubular structures and have been used for damaged blood vessels, biliary ducts, and other similar organs. The stents are an improvement over PTCA procedures because the implanted stent holds the intimal flap and plaque against the inner wall of the vessel preventing it from blocking the vessel.
Prior art stents have some functional limitations due to their current design. For example, the prior art stent can collapse when it is bent around a sharp angle. What is needed is an improved stent that is more flexible and can be implanted in tightly bent vessels.